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Test for Contaminants in Liquid and Gas Environments

IP.com Disclosure Number: IPCOM000084290D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

DiGiacomo, G: AUTHOR [+2]

Abstract

A method is provided for identifying contaminants in the environment of a component, and for calculating the effect that these contaminants have on the life of the components. Metal films of interest are allowed to react with the specific environment to which the metal is normally exposed, and the product is quantitatively analyzed physically and chemically. Specific applications for this test are the common solders.

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Test for Contaminants in Liquid and Gas Environments

A method is provided for identifying contaminants in the environment of a component, and for calculating the effect that these contaminants have on the life of the components. Metal films of interest are allowed to react with the specific environment to which the metal is normally exposed, and the product is quantitatively analyzed physically and chemically. Specific applications for this test are the common solders.

A thin film of lead, lead-tin, or lead-indium is vacuum deposited on a glass slide. The slide is placed in the environment for a suitable time (100 hours or more) at a suitable temperature (e.g., 55 degrees C). The lead reacts with the contaminants and forms a surface corrosion layer. The elements in the corrosion layer are detected by conventional techniques. The thickness of the corrosion layer is measured by an electrical resistance test.

The thickness, r, of the corrosion film is related to the characteristics of the corrosion elements and to the conditions of the test according to the following equation: r = at/n/e/(delta H/R)(1/Tb-1/T)/.

The terms a and n are constants that depend on the contaminants; t is the time during which corrosion occurs under the test conditions or, by extrapolation, under the normal operation of the component; delta H is the activation energy of the reaction process; R is the gas constant; Tb is the temperature of the test; and T is the temperature for the normal ope...